Apple's outright said it's a matter of Microsoft agreeing to license Windows on ARM for consumers. Right now putting Windows on an ARM Mac is about as legal as Hackintoshing.
I don't think that's what Apple said at all–they just said the ball is in their court, which means that they want Microsoft to write Bootcamp essentially.
Yeah. Someone - cough cough Microsoft - would need to be convinced to write a Boot Camp Assistant app equivalent (okay), a Windows bootloader (okay), various device drivers for Apple Silicon hardware revisions for Windows (big ugh), graphics drivers for Apple Silicon GPUs for Windows (VERY big ugh). Microsoft will need to very motivated to distribute Windows on ARM for this to happen, even if Apple gives them access to all the info they need which is not a given by any means.
...I don't think this is going to happen, and Apple probably doesn't either.
Apple have developed Bootcamp and provided drivers so far for Intel Mac. But shipping Bootcamp for Windows ARM would be an EULA violation until Microsoft loosen theirs conditions. Changing this is literally step 1.
Wether Apple would develop Bootcamp for ARM or not is purely theoretical discourse until then.
The only driver Apples needed to develop for Windows are Mac specifics though, like the stuff that was managed by the T1. Not trivial, but not the end of the world to have to make. Things like wifi drivers and especially the graphics drivers are just the chip vendor's standard preexisting Windows drivers.
Apple is now the vendor of at least the GPU. I don't think they're going to write a Windows driver for that - the incentives are just not there.
What you were possibly remembering was that Windows on ARM when it was first introduced only supported emulating x86 apps. Although x64 emulation is currently in preview.